They like to fly a bit, but mine get their exercise outside, and even then, they do a little flying then mostly stay on the ground scratching. So I think artsyrobin is right, esecially if we're talking Seramas here. They are short! Mine have about 20" from the top of the shavings right now, and that allows for a small perch that sits about 6-8" of the ground. They have to duck to go under the perch, but it's not hard for them, or they can hop over it, but they really do like the perch to hang out on or sleep on. If they'll be in the house, you don't need anything more than some netting for the top, so that should be inexpensive??
I'm not sure how strong the cage is against predators, so it probably shouldn't be used outside unless you're really in an area that has none. Of course that usually means you just don't see 'em

But ya, I know you want this for the house. Seems actually nice. I hate to say it, but it also seems inexpensive, 'cause cages cost a small fortune!!! Ugh!